The overall objective of this Phase I program is to provide enabling technology to carry out experiments in gene regulation without having to obtain microbiological expertise or use radioactive materials. The research objectives are to demonstrate methods for labeling synthetic oligonucleotide probes with hapten-conjugated nucleotides and using these labeled probes for the detection of specific mRNA by in situ hybridization immunohistochemistry or solution hybridization with spectrophotometric quantification of immunoenzyme reaction product. While these studies will be carried out with brain proenkephalin mRNA as the focus, the technology should have broad applicability to the study of diverse mRNAS in a variety of biological systems. This technology will form the basis for further development of novel research and diagnostic products, which should enhance research efforts in basic and clinical neurosciences. The colorimetric detection of DNA-RNA hybrids will eliminate the need for radioactivity and thus allow hybridization technology to gain broader laboratory utility.